Combinatorial Optimization has its roots in combinatorics, operations research, and theoretical computer science. It is one of the youngest and most active areas of discrete mathematics. A main motivation is that thousands of real-life problems can be formulated as combinatorial optimization problems and thus be studied from an abstract and unified point of view. This has had an enormous influence on the advancement of theory and the development of algorithms. This lecture will survey the state of the art for some of the basic combinatorial optimization problems and illustrate its algorithmic techniques for selected problems from telecommunication and traffic management.